The present invention relates to fluid metal handling means and, more particularly, to new and improved fluid metal pumping and metering means requiring no valves or moving parts in the metal flow path.
In the process of casting metal objects, molten metal must be transferred from a source such as a crucible to the molds or dies to be filled. If this process is to be accomplished through piping arrangements rather than by ladeling, certain problems arise in measuring the quantity of molten metal to be transferred. The measuring is commonly done by filling a known volume with the molten metal and then delivering it to the mold. This procedure suffers from several disadvantages. First, if a change in the amount of metal destined for the mold is to be made, the container measuring the known volume must be changed. Second, this procedure requires the use of valves and pumps having moving parts which contact the molten metal. This is disadvantageous in that the molten metal can sometime solidify and obstruct the functioning of the moving parts and also in the fact that certain molten metals are highly corrosive and can degrade these moving parts. Third, if the casting process is interrupted in a manner which causes molten metal to be isolated in a place distant from the crucible and mold, problems can arise in controlling the temperature of the isolated metal.